Electra-mechanical devices are used in a wide range of applications. Such devices typically include an electromagnetic coil which can be energized to exert a force on a component formed of magnetic material, hereinafter referred to as an armature. The force exerted on the armature moves the armature and this movement is then used to provide a desired effect, such as operation of a control mechanism, or moving electrical contacts into, or out of, contact.
The amount of electrical current that is required to create a magnetic force in the electromagnetic coil sufficient to move the armature can depend upon a wide variety of factors, including, but not limited to, the design of the coil and the mass of the armature. Another one of the factors determining the amount of electrical current required for desired movement of an armature is the distance between the electromagnetic coil and the armature, which is typically referred to as the “air gap” through which the magnetic force that acts on the armature must pass.
An electro-mechanical device with a smaller air gap will require less electrical current to operate than an otherwise identical device with a larger air gap. A minimum air gap must exist, however, to allow movement of the armature to occur. Thus, where it is desired to limit the electrical current required to operate the electro-mechanical device, it is often desired to provide an air gap of a given size which is less than some maximum value, but more than a minimum value.
For many electro-mechanical devices, assembling the device to obtain a desired air gap is straightforward and a suitable physical measuring device can be employed to properly establish the air gap. In other circumstances, however, it can be problematic to establish a desired air gap. For example, in small electro-mechanical devices, or with electro-mechanical devices occupying tight packaging volumes or enclosures, it may not be possible to position a physical measuring device in the vicinity of the electromagnetic oil and/or armature during assembly.
Accordingly, it is desired to have an electro-mechanical device that includes a desired air gap and a method of assembly for an electro-mechanical device to obtain a desired air gap.